public static void FindTextOfTextBlocks(GrayImage grayImage, List <TextBlock> textBlocks, bool isHorizontalTextLayout)
{
blocks = textBlocks;
image = grayImage;
isHorizontalText = isHorizontalTextLayout;
ProcessFirstBlock();
int i;
for (i = 1; i < blocks.Count - 1; i++)
{
if (blocks[i].IsNeedOCRProcess)
{
ProcessPotentialMergeBlock(ref i);
}
else
{
ClassifyTextBlock(blocks[i]);
isPreviousMerge = false;
}
}
if (i < blocks.Count)
{
ProcessFinalBlock();
}
PostProcess.Start(blocks, isHorizontalText);
}
public static void LinearNormalization(GrayImage img, TextBlock block)
{
FindAspectRatioAdaptiveNormalization(block.Height, block.Width, FeatureExtaction.SHAPE_NORM_TARGET_LENGTH);
float width = (float)block.Width / NormWidth;
float height = (float)block.Height / NormHeigth;
int maxColumnIndex = block.Right;
int maxRowIndex = block.Bottom;
int shiftLeft = block.Left;
int shiftTop = block.Top;
int imgWidth = img.Width;
int length = NormWidth * NormHeigth;
Parallel.For(0, length, (index) =>
{
int j = index % NormWidth;
int i = index / NormWidth;
int x0 = (int)Math.Floor(width * j) + shiftLeft;
int y0 = (int)Math.Floor(height * i) + shiftTop;
int imgIndex = imgWidth * y0 + x0;
if (imgIndex < img.Pixels.Length)
{
Pixels[index] = img.Pixels[imgIndex];
}
else
{
Pixels[index] = 0;
}
});
}
private static void CorrectBlockWidth(GrayImage image, TextBlock block)
{
int right = 0;
int left = HorizontalTextProjection.MAX_INT;
int width = image.Width;
int topIndex = block.Top;
int bottomIndex = block.Bottom + 1;
int startIndex = block.Left;
int stopIndex = block.Right + 1;
for (int rowIndx = topIndex; rowIndx < bottomIndex; rowIndx++)
{
int index = rowIndx * width + startIndex;
for (int j = startIndex; j < stopIndex; j++)
{
if (image.Pixels[index] > 0)
{
if (j < left)
{
left = j;
}
if (j > right)
{
right = j;
}
}
index++;
}
}
block.Width = right - left + 1;
block.Left = left;
block.Right = right;
}
private static bool SplitMultiBlock(List <TextBlock> blocks, uint[] density, GrayImage image, int i)
{
int splitIndex = GetSplitIndexOfBlock(blocks[i], density);
if (splitIndex < blocks[i].Top + 2 || splitIndex > blocks[i].Bottom - 2)
{
return(false);
}
TextBlock bottomHalf = new TextBlock()
{
Left = blocks[i].Left,
Right = blocks[i].Right,
Top = splitIndex,
Bottom = blocks[i].Bottom,
Height = blocks[i].Bottom - splitIndex + 1,
Type = TextBlockType.Multi
};
CorrectBlockWidth(image, bottomHalf);
blocks.Insert(i + 1, bottomHalf);
blocks[i].Bottom = splitIndex;
blocks[i].Height = blocks[i].Bottom - blocks[i].Top + 1;
CorrectBlockWidth(image, blocks[i]);
return(true);
}
public static bool IsWhiteOnBlack(GrayImage image, int threshold)
{
int width = image.Width;
int height = image.Height;
int temp = 0;
int lastRow = (height - 1) * width;
for (int j = 0; j < width; j++)
{
temp += image.Pixels[j];
temp += image.Pixels[lastRow + j];
}
int lastCol = width - 1;
for (int i = 0; i < height; i++)
{
temp += image.Pixels[i * width];
temp += image.Pixels[i * width + lastCol];
}
double avgDen = (double)(temp) / ((width + height) * 2);
if (avgDen < threshold)
{
return(true);
}
else
{
return(false);
}
}
public static void StartBinarized(GrayImage image)
{
var otsu = GetOtsuBinarizedParams(image);
bool isWhiteOnBlack = IsWhiteOnBlack(image, otsu.Threshold);
OtsuBinarizedImage(image, otsu, isWhiteOnBlack);
}
private static void DebugTextExtract(GrayImage image, List <TextBlock> textBlocks, ShowImageHandle showImageFunction)
{
var displayImage = image.Clone();
Helper.DrawTextBlockBox(displayImage, textBlocks);
showImageFunction(displayImage);
}
private static long GetRawMoment00(GrayImage img, TextBlock block)
{
int shiftTop = block.Top;
int shiftLeft = block.Left;
int width = img.Width;
long moment = 0;
int start = shiftTop * width + shiftLeft;
int textBlockWidth = block.Width;
int textBlockHeight = block.Height;
int skipWidth = width - textBlockWidth;
for (int i = 0; i < textBlockHeight; i++)
{
for (int j = 0; j < textBlockWidth; j++)
{
if (img.Pixels[start] > 0)
{
moment++;
}
start++;
}
start += skipWidth;
}
return(moment);
}
public static void DrawTextBlockBox(GrayImage image, List <TextBlock> blocks)
{
foreach (var block in blocks)
{
int start = block.Top * image.Width + block.Left;
for (int i = start; i < start + block.Width; i++)
{
image.Pixels[i] = 255;
}
start = block.Bottom * image.Width + block.Left;
for (int i = start; i < start + block.Width; i++)
{
image.Pixels[i] = 255;
}
for (int i = block.Top * image.Width + block.Left; i < block.Bottom * image.Width; i += image.Width)
{
image.Pixels[i] = 255;
}
for (int i = block.Top * image.Width + block.Right; i < block.Bottom * image.Width; i += image.Width)
{
image.Pixels[i] = 255;
}
}
}
public GrayImage Clone()
{
GrayImage cloneImg = new GrayImage(Width, Height);
cloneImg.Pixels = new byte[Pixels.Length];
Pixels.CopyTo(cloneImg.Pixels, 0);
return(cloneImg);
}
private static int[] GetImageHistogram(GrayImage image)
{
int[] hist = new int[NUMBER_OF_GRAY_LEVELS];
for (int i = 0; i < image.Pixels.Length; i++)
{
hist[image.Pixels[i]] = hist[image.Pixels[i]] + 1;
}
return(hist);
}
private static void DebugShapNormilization(GrayImage image, List <TextBlock> textBlocks, ShowImageHandle showImageFunction)
{
foreach (var b in textBlocks)
{
ShapeNormalization.LinearNormalization(image, b);
GrayImage bImag = new GrayImage(ShapeNormalization.NormWidth, ShapeNormalization.NormHeigth);
bImag.Pixels = ShapeNormalization.Pixels;
showImageFunction(bImag);
}
}
public static List <TextBlock> RecognizeOneWord(GrayImage image)
{
ColorConverter.StartBinarized(image);
var textBlock = Classifier.ClassifyOneText(image);
var blocks = new List <TextBlock>(1);
blocks.Add(textBlock);
return(blocks);
}
public static List <TextBlock> RecognizeSentences(GrayImage image)
{
ColorConverter.StartBinarized(image);
var textBlocks = TextExtraction.FindTextBlocks(image);
if (textBlocks.Count > 0)
{
Classifier.FindTextOfTextBlocks(image, textBlocks, TextExtraction.IsHorizontalText);
}
return(textBlocks);
}
private static List <TextBlock> ProcessHorizontalLines(GrayImage image, uint[] vertical)
{
List <TextBlock> textBlocks = new List <TextBlock>();
List <SplitMultiLines.Line> textLines = SplitMultiLines.SplitProjectDensity(vertical);
for (int i = 0; i < textLines.Count; i++)
{
var density = Projection.ProjectSubImageOnHorizontalLine(image, textLines[i]);
textBlocks.AddRange(HorizontalTextProjection.FindAllTextBlock(image, density, textLines[i], i));
}
return(textBlocks);
}
private static List <TextBlock> ProcessVerticalLines(GrayImage image, uint[] horizontal)
{
List <TextBlock> textBlocks = new List <TextBlock>();
List <SplitMultiLines.Line> textLines = SplitMultiLines.SplitProjectDensity(horizontal);
textLines.Reverse(); //Japanese column is going from right to left
for (int i = 0; i < textLines.Count; i++)
{
var density = Projection.ProjectSubImageOnVerticalLine(image, textLines[i]);
textBlocks.AddRange(VerticalTextProjection.FindAllTextBlock(image, density, textLines[i], i));
}
return(textBlocks);
}
public static TextBlock ClassifyOneText(GrayImage grayImage)
{
isHorizontalText = true;
image = grayImage;
TextBlock block = InitOneTextBlock();
block.Type = TextBlockType.Single;
block.IsNeedOCRProcess = false;
block.Ratio = 1;
block.HeighRatio = 1;
ClassifyTextBlock(block);
return(block);
}
/// <summary>
/// Get sub images from the results returned by SplitProjectDensity()
/// </summary>
/// <param name="image">Image that has been analyzed and split by Split(uint[] density)</param>
/// <param name="space">A split block</param>
/// <param name="isHorizontal">True if text layout is horizontal</param>
/// <returns></returns>
public static GrayImage GetSubImage(GrayImage image, Line block, bool isHorizontal)
{
GrayImage subImage;
if (isHorizontal)
{
subImage = GetHorizontalSplitImage(image, block);
}
else
{
subImage = GetVerticalSplitImage(image, block);
}
return(subImage);
}
private static List <TextBlock> ExtractTextBlocks(GrayImage image, bool isHorizontalText)
{
IsHorizontalText = isHorizontalText;
if (isHorizontalText)
{
var vertical = Projection.ProjectOnVerticalLine(image);
return(ProcessHorizontalLines(image, vertical));
}
else
{
var horizontal = Projection.ProjectOnHorizontalLine(image);
return(ProcessVerticalLines(image, horizontal));
}
}
/// <summary>
/// This function is for debugging purposes only
/// </summary>
/// <param name="image"></param>
/// <param name="showImageFunction"></param>
/// <returns></returns>
public static List <TextBlock> Start(GrayImage image, ShowImageHandle showImageFunction)
{
ColorConverter.StartBinarized(image);
var textBlocks = TextExtraction.FindTextBlocks(image);
DebugTextExtract(image, textBlocks, showImageFunction);
//DebugShapNormilization(image, textBlocks, showImageFunction);
if (textBlocks.Count > 0)
{
Classifier.FindTextOfTextBlocks(image, textBlocks, TextExtraction.IsHorizontalText);
}
return(textBlocks);
}
public static GrayImage ConvertFloatToByteImage(float[] img, int height, int width)
{
GrayImage imageOut = new GrayImage(width, height);
imageOut.Pixels = new byte[width * height];
float max = float.MinValue;
float min = float.MaxValue;
for (int i = 0; i < img.Length; i++)
{
if (img[i] > max)
{
max = img[i];
}
if (img[i] < min)
{
min = img[i];
}
}
for (int i = 0; i < img.Length; i++)
{
img[i] += -min;
}
float maxRange = max - min;
float scale = 255 / maxRange;
float value;
for (int i = 0; i < img.Length; i++)
{
value = img[i] * scale;
if (value > 255)
{
value = 255;
}
else if (value < 0)
{
value = 0;
}
imageOut.Pixels[i] = (byte)value;
}
return(imageOut);
}
public static void MomentNormalization(GrayImage img, TextBlock block)
{
var M10 = GetRawMoment10(img, block);
var M01 = GetRawMoment01(img, block);
var M00 = GetRawMoment00(img, block);
if (M00 == 0)
{
LinearNormalization(img, block);
}
var cX = M10 / M00;
var cY = M01 / M00;
var u20 = GetRawMoment20(img, block) - cX * M10;
var u02 = GetRawMoment02(img, block) - cY * M01;
if (u20 <= 0 || u02 <= 0)
{
LinearNormalization(img, block);
}
double deltaX2 = u20 * 16.0;
double deltaY2 = u02 * 16.0;
double deltaX = Math.Sqrt(deltaX2);
double deltaY = Math.Sqrt(deltaY2);
FindAspectRatioAdaptiveNormalization(deltaY, deltaX, FeatureExtaction.SHAPE_NORM_TARGET_LENGTH);
double halfWidth = NormWidth / 2;
double halfHeight = NormHeigth / 2;
int shiftTop = block.Top;
int shiftLeft = block.Left;
int imgWidth = img.Width;
int textWidth = block.Width;
int textHeight = block.Height;
int length = NormWidth * NormHeigth;
Parallel.For(0, length, (index) =>
{
int i = index / NormWidth;
int j = index % NormWidth;
double xs = deltaX * (j - halfWidth) / NormWidth + cX;
double ys = deltaY * (i - halfHeight) / NormHeigth + cY;
int x0 = GetOriginalPixelCoordinate(xs, cX, deltaX, deltaX2, textWidth);
int y0 = GetOriginalPixelCoordinate(ys, cY, deltaY, deltaY2, textHeight);
int originalIndex = (y0 + shiftTop) * imgWidth + x0 + shiftLeft;
Pixels[index] = img.Pixels[originalIndex];
});
}
private static List <TextBlock> ExtractTextBlocks(GrayImage image)
{
var vertical = Projection.ProjectAndFindVarianceOnVerticalLine(image);
var horizontal = Projection.ProjectAndFindVarianceOnHorizontalLine(image);
IsHorizontalText = Projection.IsHorizontalTextLayout(vertical.Vtheta, horizontal.Vtheta);
if (IsHorizontalText)
{
return(ProcessHorizontalLines(image, vertical.Density));
}
else
{
return(ProcessVerticalLines(image, horizontal.Density));
}
}
public static List <TextBlock> FindTextBlocks(GrayImage image, bool?isHorizontal = null)
{
List <TextBlock> textBlocks;
if (isHorizontal == null)
{
textBlocks = ExtractTextBlocks(image);
}
else
{
textBlocks = ExtractTextBlocks(image, (bool)isHorizontal);
}
RemoveNoiseTextBlocks(textBlocks);
return(textBlocks);
}
public static void OtsuBinarizedImage(GrayImage image, Otsu otsu, bool isWhiteOnBlack)
{
if (isWhiteOnBlack)
{
Parallel.For(0, image.Pixels.Length, (i) =>
{
image.Pixels[i] = image.Pixels[i] > otsu.Threshold ? image.Pixels[i] : MIN_BINARY;
});
}
else
{
Parallel.For(0, image.Pixels.Length, (i) =>
{
image.Pixels[i] = image.Pixels[i] > otsu.Threshold ? MIN_BINARY : (byte)(MAX_BINARY - image.Pixels[i]);
});
}
}
private static List <TextBlock> InitTextBlocks(GrayImage image, uint[] density, int lineIndex)
{
sumBlockWidth = 0;
sumBlockHeight = 0;
List <TextBlock> blocks = new List <TextBlock>();
bool isStartBlock = false;
TextBlock block;
int top = 0;
for (int j = 1; j < density.Length; j++)
{
if (density[j] > 0)
{
if (!isStartBlock)
{
isStartBlock = true;
top = j;
}
}
else
{
if (isStartBlock)
{
block = GetBlock(image, top, j);
block.LineIndex = lineIndex;
blocks.Add(block);
sumBlockHeight += block.Height;
sumBlockWidth += block.Width;
}
isStartBlock = false;
}
}
if (isStartBlock)
{
block = GetBlock(image, top, image.Height);
block.LineIndex = lineIndex;
blocks.Add(block);
sumBlockHeight += block.Height;
sumBlockWidth += block.Width;
}
return(blocks);
}
private static void GetOutLinePixelsPosition(GrayImage image, ref int left, ref int right, ref int top, ref int bottom)
{
if (left > 0)
{
left--;
}
if (right < image.Width - 1)
{
right++;
}
if (top > 0)
{
top--;
}
if (bottom < image.Height - 1)
{
bottom++;
}
}
public static uint[] ProjectOnHorizontalLine(GrayImage image)
{
int width = image.Width;
var density = new uint[width];
Parallel.For(0, density.Length, (j) =>
{
uint lineProject = 0;
for (int index = j; index < image.Pixels.Length; index += width)
{
if (image.Pixels[index] > 0)
{
lineProject++;
}
}
density[j] = lineProject;
});
return(density);
}
public static uint[] ProjectOnVerticalLine(GrayImage image)
{
int width = image.Width;
var density = new uint[image.Height];
Parallel.For(0, density.Length, (i) =>
{
int index = i * width;
uint lineProject = 0;
for (int j = 0; j < width; j++)
{
if (image.Pixels[index] > 0)
{
lineProject++;
}
index++;
}
density[i] = lineProject;
});
return(density);
}
public static uint[] ProjectSubImageOnHorizontalLine(GrayImage image, SplitMultiLines.Line line)
{
int width = image.Width;
var density = new uint[width];
int stop = line.StartSpace * width;
Parallel.For(0, width, (j) =>
{
int start = width * line.StartText + j;
uint lineProject = 0;
for (int index = start; index < stop; index += width)
{
if (image.Pixels[index] > 0)
{
lineProject++;
}
}
density[j] = lineProject;
});
return(density);
}
